Inner boot tongue of a ski boot

ABSTRACT

The part of a boot in question, in particular an inner-boot tongue of a ski boot, is essentially constituted by an outer part (1) made of impermeable semi-rigid plastic having an alveolate structure (6), covered directly by a foam-type padding (4) and by a woven or knitted liner (5). The air contained in the alveoles of the alveolate structure forms a particularly effective damper cushion in dynamic compression.

This application is a continuation of application Ser. No. 08/280,788,filed Jul. 26, 1994, now abandoned.

FIELD OF THE INVENTION

The subject of the present invention is part of a boot, other than thesole, in particular an inner-boot tongue for a ski boot, essentiallyconstituted by an outer part made of impermeable semi-rigid plastic, bya foam-type padding and by a woven or knitted liner.

PRIOR ART

Such tongues are commonly used in inner boots of ski boots. The outerpart is intended to support the pressure of the boot-clamping buckles,the role of the foam being to ensure that the pressure exerted by thebuckles does not result in a painful localized pressure. However, goodholding of the foot in the boot requires relatively high clamping of thebuckles and the skier often has the impression of a hard spot on thetibia despite the presence of the foam. This feeling of a hard spot,which may become painful, is due in fact to crushing of the foam. Itturns out that even if this foam is not completely crushed statically bythe buckle, it is totally crushed, in a repetitive and instantaneousway, in dynamic mode, by the repeated flexing of the leg, when the skieris skiing.

The tongue described in the document CH-A-677,588 has, in addition tothe foam, a thick soft nonwoven textile layer. This layer, whichsubstantially increases the thickness of the tongue, also ends up bybeing totally crushed by the action of the boot buckles.

A tongue is known, from the document EP-A-0,468,532, which comprises apocket fitted between two foam layers, this pocket being filled with aliquid having a particular viscosity and mixed with solid particles,this mixture being commercially available under the FLOLITE trademark.Such a material has the advantage of ensuring that the shape of thetongue matches the shape of the tibia, but once it has adopted thisshape, it does not act as a damper given the incompressibility of theliquid. Furthermore, if this material acts so as to distribute thepressure over the tibia, when working dynamically, its viscosity is suchthat it does not have time to flow under the pressure of the buckle andthe skier again feels the localized pressure of this buckle.

It has already been envisaged to use a compressible fluid, that is tosay a gas, in the manufacture of soles of sports shoes. Such shoes aredescribed in, for example, the U.S. Pat. Nos. 4,183,156 and 4,219,945.The gas is contained under pressure in a multiplicity of mutuallycommunicating chambers. This structure is intended to damp shocks whilestill ensuring a certain elastic response. Now, it is known thatsynthetic materials are not perfectly impermeable to gas, so that such astructure requires the use of special synthetic materials and the choiceof a suitable gas, so as to maintain a sufficient pressure for severalyears. The use of such a structure for parts of boots other than thesole, in particular tongues, as proposed in the Patent FR 2,586,342,therefore has no real advantage, especially as the compressionconditions are not comparable to that of a shoe sole as regards themagnitude of the permanent pressure and the pressure points.

SUMMARY OF THE INVENTION

The object of the present invention is to produce, as simply aspossible, part of a boot, other than the sole, ensuring good damping,that is to say the absorption of an instantaneous overpressure due to ashock or to a boot-tightening means working dynamically during theflexing of the leg. The said part must also ensure that the foot iscomfortable under static pressure by means of a good distribution of theexternal pressure.

In order to achieve this result, the part of a boot, according to theinvention, is characterized in that the inner face of the outer part ofthe tongue has an alveolate structure covered directly by the padding.

The alveolate structure may, for example, be of the goffered orhoneycomb type.

The foam is preferably an open-cell foam, but it could be a closed-cellfoam.

The alveoles are closed by the padding foam, so that a certain quantityof air remains trapped in the alveoles. When clamping the boot, the foampenetrates only very slightly into the alveoles. The air trapped in thealveoles constitutes a cushion whose effect will be added to the effectof the foam, when working dynamically, that is to say during repeatedflexing of the leg in the case of a tongue. During dynamic compression,this being added to the static clamping pressure, the foam in factpenetrates further, by deforming, into the alveoles and the aircontained in the alveoles is compressed. The elasticity resulting fromthis compression has the effect of rapidly pushing back the foam out ofthe alveoles when the dynamic compression stops.

In the case of padding made of open-cell foam, the compressed air in thealveoles escapes through the foam and the inner liner. Given the veryhigh pressure drop in the foam, the air, when working dynamically, doesnot, however, have the time to escape from the alveoles completely, sothat part of this air remains in compressed form in the alveoles, theelasticity resulting from this compression also having the effect ofrapidly pushing back the foam out of the alveoles when the dynamiccompression stops.

Thus, contrary to the shock-absorbing soles of sports shoes, it is notnecessary to have a gas-impermeable envelope. On the contrary, in thepreferred embodiment, advantage is taken of the non-impermeability ofthe foam and of the liner. In addition, not only is the novel structureof the tongue produced without any additional element, but it makes itpossible to dispense with the thick nonwoven textile layer present inthe tongue according to the Patent CH 677,588.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawing depicts one embodiment of the invention, as anexample.

FIG. 1 is a view, from the outside, of a complete tongue.

FIG. 2 is a side view of the same tongue unstitched, the foam part ofwhich having been partially separated from the plastic part.

FIG. 3 is a view just of the plastic part, seen from inside the innerboot.

FIG. 4 is an exploded diagrammatic view of part of the tongue with analveolate structure different from that depicted in FIGS. 2 and 3.

FIGS. 5, 6 and 7 illustrate the behavior of the tongue during dynamiccompression.

FIG. 8 depicts an inner boot equipped with a tongue according to FIG. 1.

FIG. 9 is a schematic view of a generic ski boot incorporating theteachings of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The tongue depicted in FIG. 1 comprises a part 1 made of semi-rigidplastic, of curved shape in the form of a riding saddle, reinforced, inthe embodiment depicted, by a plastic cover 2 partially covering theplastic part 1. The plastic part 1 is terminated, at its lower end, by atab 3 equipped with a positioning notch for its attachment to a point 9on the inner boot 10 depicted in FIG. 8. The inner side of the plasticpart 1 is coated with a layer of open-cell foam 4 covered by a woven orknitted liner 5 stitched to the plastic part 1.

As may be seen in FIG. 2, the inner face of the plastic part 1 has ahoneycomb alveolate structure 6.

The honeycomb structure 6 could be replaced by another alveolatestructure, for example a goffered-type structure 6' such as depicted inFIG. 4 where, in exploded view, the layer of foam 4 and the liner 5 mayalso be seen.

The behavior of the structure of the tongue during dynamic compressionwill now be described in conjunction with FIGS. 5 to 7.

FIG. 5 depicts the state of the tongue at the beginning of compressionwhen the pressure has only a value P1. The pressure P1 has the effect ofcompressing the liner 5 and, to a certain extent, the padding 4. Thispadding 4 bears against the end of the ribs formed by the alveolatestructure 6. The air 7 contained in the alveoles of this alveolatestructure has not yet been compressed.

FIG. 6 depicts the state of the tongue when the pressure has reached anintermediate value P2, which has the effect of compressing the padding 4which deforms and penetrates into the alveoles 7 of the alveolatestructure, compressing the air contained in these alveoles. It should bepointed out that the air contained in the padding 4 is also compressed.

FIG. 7 shows the tongue when the pressure has reached its maximum valueP3, that is to say at the peak of the pressure pulse. During thecompression phase, the compressed air in the alveoles 7 escapes slowlythrough the padding 4 and the liner 5. By reason of the very highpressure drop across the padding 4, which pressure drop is furtherincreased by the compressed air in the open cells of this padding, thepressure of the air decreases relatively slowly in the alveoles. Thepressure P generally disappears before the pressure of the air in thealveoles has been substantially decreased. Thus, until the end of thepressure pulse, the tongue maintains a certain quantity of compressedair, ensuring very high elasticity of the tongue to the compression andpreventing any feeling of a hard spot at the point of a localizedpressure on the tongue, which localized pressure is especially due tothe boot-tightening means.

The state of the tongue, under static clamping compression, correspondsto the state depicted in FIG. 5 or to an intermediate state between thestate depicted in FIG. 5 and the state depicted in FIG. 6, depending onthe force with which the boot is clamped.

FIG. 9 shows a generic schematic drawing of a ski boot and the innerboot.

The structure according to the invention can be applied to any part of aboot or an inner boot, other than the sole, in particular the lateralparts level with the malleoli, or the tops and sides of the tarsal andmetatarsal part.

The alveolate structure does not necessarily have to be regular, asdepicted, but the alveoles could have a variable depth and shape. Asregards the foam, this could be complex and, in particular, beconstituted by foams of different densities and/or foams having open andclosed cells.

I claim:
 1. A ski boot containing an inner boot, said inner boot having a sole and an upper part and wherein said upper part has a padded part comprising;an outer part which is made of impermeable semi-rigid plastic; an alveolate structure on the inside of the outer part having alveoles hermetically closed on the outside by said outer part; a foam-padding lying directly on the open side of the alveoles, so that the alveoles are taken in sandwich between said outer part and the foam-padding; and an inner liner lying on the foam-padding, in such a manner that during dynamic compression of the padded part the foam penetrates further into the alveoles, compressing thereby the air trapped in said alveoles, so that instantaneous overpressures are damped.
 2. A ski boot as claimed in claim 1, wherein the foam-type padding is an open-cell foam.
 3. A ski boot as claimed in claim 1, wherein the padded part is a tongue.
 4. A ski boot as claimed in claim 3, wherein the liner is made from a woven or knitted material.
 5. A ski boot as claimed in claim 3, wherein the foam-type padding is an open-cell foam.
 6. A ski boot as claimed in claim 1, wherein the alveolate structure has a honeycomb configuration.
 7. A ski boot as claimed in claim 1, wherein the alveolate structure has a waffle configuration. 